FEAT: draft-saving feature for messages, which automatically sends them when the internet is restored.

[dhairyashiil]

As an EmbeddedChat developer

I need to:
Implement a draft-saving feature for messages, with automatic sending when the internet is restored.

So That:
It will prevent message loss during internet drops by saving drafts automatically.
No need to manually save drafts or retry sending later.

Acceptance Criteria

• Add a draft-saving feature for messages, which automatically sends them when the internet is restored.
• If multiple messages are queued while offline, ensure that all of them are sent in order once the connection is restored, as long as the user remains on that screen.
• There is no need to send the messages if the user closes the tab.
• For the last unsent message that was typed, populate it back into the input box when the user returns to the page.